T.J. Waldburger, 24, has been a professional fighter since he was 17. Competing in a hurt sport against grown men as a teenager is always admirable, but to rack up 13 submission wins in the process is even more impressive. Most recently, Waldburger spoiled Nick Catone’s welterweight debut in December with a sleep-inducing triangle choke, one of 2012’s nicest “Submission of the Night” performances.

A Texas-tough fighter on a self-proclaimed jiu-jitsu mission, Waldburger has gone the distance just once in the UFC – in his promotional debut. His two octagon losses have come against current top contender Johny Hendricks and consummate veteran Brian Ebersole.

14. Carla Esparza (9-2 MMA, 3-0 IFC)

Carla Esparza, a Team Oyama standout, has turned it up a notch. Invicta FC’s inaugural strawweight champion went 25 minutes to capture the vacant title over Bec Hyatt. The 25-year-old’s only two defeats were under the Bellator banner to elite fighters Megumi Fujii and Jessica Aguilar. “Cookie Monster” currently rides a four-fight win streak, which includes a perfect 3-0 Invicta record, since dropping a split decision to Aguilar. Esparza’s affinity for tagging leg kicks to the end of her combinations – along with apt counters and increased takedown ability – showcases her ability to build championship tools on the job. Female fighting expands thanks in part to dedicated 115-pound competitors such as Esparza and others not in the UFC’s 135-pound women’s division.

13. Erik Koch (13-2 MMA, 2-1 UFC)

The 24-year-old Duke Roufus protege’s nickname “New Breed” rings true. The WEC vet’s recent four-fight win streak included two wins upon his arrival in the UFC. That earned Koch a shot at Jose Aldo for the UFC’s featherweight crown. Injuries bounced Koch from the fight until Ricardo Lamas’ elbows further removed the five-year veteran from 145-pound title shots. The image of a bloody KO loss on UFC on FOX 6 in January is difficult to forget; however, Koch’s 77 percent finishing rate and four consecutive wins after losing to Chad Mendes suggest Koch is capable of coming back and asserting his contender aspirations once again.

12. Patricio “Pitbull” Freire (17-2 MMA, 5-2 BFC)

The 25-year-old Bellator tournament champion came up short against featherweight titleholder Pat Curran this past month, but the 25-minute contest showcased Freire’s technique and sheer toughness. His other career defeat also came in a high-stakes Bellator bout, where he lost a dubious split decision to “The Baddest Man on the Planet,” world champion wrestler and future Bellator featherweight champ Joe Warren. Freire’s 76 percent finishing rate includes wins against Bellator staples Wilson Reis and Georgi Karakhanyan.

His competitive Bellator resume and Team Nogueira banner bodes well for the young Brazilian’s future.

11. Stefan Struve (25-5 MMA, UFC 9-3)

Stefan Struve is the tallest fighter in UFC history and possesses an 84.5-inch reach. At 24 years old, he’s got four years in the octagon and a current four-fight win streak he carries into Japan versus Mark Hunt at UFC on FUEL TV 8 in March. Six consecutive UFC finishes in victory reminds us that “Skyscraper” learns how to utilize his height, reach and flirtation with the UFC’s 265-pound limit better in each outing. Increased confidence and world-class training are the only elements standing between Struve and a serious heavyweight title opportunity. Those things accumulate over time. The giant from the Netherlands awaits opportune timing to coincide with his evolving talent.

His detour to fight in Brazil in a Bellator-approved Shooto affair didn’t go according to anyone’s plan as Tyson Nam knocked him out in the worst way imaginable. He cut Dantas’ flying-knee attempt out of the air with a conscious-stealing right hook. “Dudu” returns to Bellator Thursday to defend his 135-pound title against teammate and Brazilian jiu-jitsu world champ Marcos Galvao. Whether or not the devastating KO derailed his dynamic game will be on display, but at 24 years old and backed by such a respected camp, Dantas is unlikely to lose a step.

9. Khabib Nurmagomedov (19-0 MMA, 3-0 UFC)

Khabib Nurmagomedov is living up to his epic “The Eagle” nickname. The Russian transplant trains alongside Gray Maynard, Josh Thomson, Jon Fitch, Luke Rockhold and Cain Velasquez at the renowned American Kickboxing Academy in San Jose, Calif. Trading in the bear winter for the California sun is already shining a light on the 24-year-old’s bright future. Undefeated in his five-year career, which includes 14 finishes, is one reason for lightweights to learn how to pronounce his name. Another: No one debuts in the UFC’s lightweight division with a three-fight win streak like Nurmagomedov has. Defeating Kamal Shalorus, Gleison Tibau and Thiago Tavares is a hell of a way to break onto the scene.

8. Erik Perez (13-4 MMA, 3-0 UFC)

Erik “El Goyito” Perez dawns a Mexican wrestler mask while walking to the cage to celebrate the fact he’s the UFC’s first Mexican-born fighter. Anchored at Greg Jackson’s camp in New Mexico, Perez’s three-for-three first-round finishes in 2012 made him a solid Rookie of the Year pick. Knocking out Ken Stone in 17 seconds is Perez’s first major accolade – the fastest KO in Zuffa’s bantamweight history.

Perez genuinely enjoys being in the fighting arena. The 23-year-old borrows traditions from Mexico’s rich boxing history, his chosen combat sport. It’s unveiled in his busy schedule as he’s pieced together an eight-fight win streak in the past two years. Both in and out of the cage, Perez contains the proper ingredients to mobilize fans while advancing up the 135-pound ladder.

7. Dustin Poirier (13-2 MMA, 5-1 UFC)

Dustin “Diamond” Poirier’s three submission victories in his past four fights demonstrate how aggression pays off in a division gunning for featherweight champ Jose Aldo. Against the “Korean Zombie” Chang Sung Jung, Poirier gave up a fourth-round brabo choke in a 2012 “Fight of the Year” candidate, which made for the lone blemish in his otherwise spotless UFC run. He successfully rebounded from his first UFC defeat with a wildly exciting December scrap that caused Jonathan Brookins to go soul-searching.

The 24-year-old, who’s now anchored at American Top Team, has 11 finishes in his 13 career wins. Stepping up against Cub Swanson on short notice this weekend at UFC on FUEL TV 7 inserts Poirier into another likely title eliminator. Swanson undeniably attained Comeback Fighter of the Year honors in 2012, so Poirier is in a stellar position to resume his foray into the upper echelon of the 145-pound weight class.

6. Pat Curran (18-4 MMA, 8-1 BFC)

Pat Curran is Bellator’s first fighter to capture tournament titles in two divisions. The Team Curran combatant worked his way to a lightweight title shot versus Eddie Alvarez, and he went the distance with the respected top-10 155-pounder, which prompted praise for his hard-fought performance. He affirmed he was fighting outside his natural weight class.

So Curran ventured to 145 pounds, where he seized Bellator’s tournament title versus former World Victory Road/Sengoku champ Marlon Sandro, which set up Curran’s relentless and unforgiving beatdown of featherweight champ Joe Warren. It was the kind of knockout that easily could have taken KO of the Year honors in 2012 if everyone wasn’t so eager to forget just how ugly the drubbing actually was (Late Stoppage 101). The 25-year-old won Bellator’s first title fight on Spike TV in an entertaining, technical 25-minute striking battle with Patricky “Pitbull” Freire. Curran is truly a world-class fighter and the most promising one not signed to a UFC contract.

Tune in Thursday for the fighters ranked No. 1 to 5 as our three-part series concludes.

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